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Biomedical subjects

L H Nielsen

Publications and source records attributed to L H Nielsen.

At least 19 recordsLinked to original sources
PubMed2002

Elimination of mange mites Sarcoptes scabiei var. suis from two naturally infested Danish sow herds using a single injection regime with doramectin.

Attempts to eliminate Sarcoptes scabiei var. suis were made in 2 naturally infested sow herds, by intramuscular (i.m.) injection of doramectin (Dectomax, Pfizer, New York, USA). A single injection strategy was used. In one of the herds, the environment was treated with an acaricide following dry cleaning of floors, walls and equipment. In the second herd, no environmental treatment was performed. Results were measured by skin lesion scoring, ear scrapings to show Sarcoptes scabiei var. suis, and calculating rubbing index throughout the observation period of 20 months following treatment. Skin lesion scores decreased and stayed low following treatment for the entire observation period. Live Sarcoptes scabiei var. suis mites were isolated prior to treatment from both herds, but not following treatment. Rubbing index decreased following treatment, but was occasionally at or above 0.4. The results of these studies indicate that elimination of Sarcoptes scabiei var. suis from 2 naturally infested herds was successful, using doramectin in a single injection strategy. Precautions must be taken to ensure adequate dosing of every pig, and to avoid reinfestation due to poor biosecurity.

Animals↗
PubMed2000

Urinary albumin excretion and 24-hour blood pressure as predictors of pre-eclampsia in Type I diabetes.

AIMS/HYPOTHESIS: To evaluate the value of 24-h blood pressure monitoring compared to office blood pressure and urinary albumin excretion in predicting pre-eclampsia in Type I (insulin-dependent) diabetes mellitus. METHODS: The study included 136 consecutive pregnancies in Caucasian women with Type I diabetes before gestation without diabetic nephropathy, anamnestic hypertension or early abortion. Values of urinary albumin excretion and office blood pressure before pregnancy and the HbA1C value at the time of conception were obtained. Microalbuminuria was defined as urinary albumin excretion of 30-300 mg/24 h in two out of three consecutive urine samples. Single measurements of 24-h urinary albumin excretion, office blood pressure and HbA1C were done five 5 times during pregnancy. In a subgroup of 74 women 24-h blood pressure measurements were done at 10 and 28 weeks of gestation. Pre-eclampsia was defined as office blood pressure higher than 140/90 mmHg accompanied by proteinuria above 0.3 g/24 h later than 20 weeks of gestation. RESULTS: Urinary albumin excretion and systolic blood pressure were higher before and throughout pregnancy in 14 women developing pre-eclampsia compared with women remaining normotensive (p <0.001; p < 0.05, respectively). By logistic regression analysis the best predictor for pre-eclampsia was microalbuminuria before pregnancy (p < 0.05) with no additive predictive effect of 24-h blood pressure or office blood pressure measurement. The night:day ratio of blood pressure was similar in the two groups. CONCLUSION/INTERPRETATION: Microalbuminuria before pregnancy is the strongest predictor of pre-eclampsia in Type I diabetes. Measuring 24-h blood pressure early in pregnancy did not improve the ability to identify women at risk.

Adult↗
PubMed2000

Gait disturbance interpreted as cerebellar ataxia after MMR vaccination at 15 months of age: a follow-up study.

Measles, mumps and rubella (MMR) vaccination was included in the Danish childhood vaccination programme in 1987. During the following 10-y period, 550 notification records of adverse events after MMR vaccination at 15 mo of age have been registered, and a total of 41 notifications have included "gait disturbance". This corresponds to a frequency of 8 per 100,000 doses of MMR vaccine used for 15-mo-old children. The symptoms and signs are characteristic of cerebellar ataxia. In 28 notifications, the descriptions by the doctors included only "gait disturbance", while in 13 an additional interpretation was included. Thirty-two parents (78%) filled in a questionnaire and 26 (63%) agreed to participate in a clinical follow-up study. The gait disturbance symptoms mainly occurred 7-14 d after the vaccination, and the duration was median 1-2 wk (range 1 d to more than 4 mo). One-third of the children had symptoms lasting more than 2 wk. Significantly more children with long duration of symptoms had some kind of complaint or clinical signs at the follow-up in 1997. Gait disturbance registered after MMR vaccination seems to be more frequent than hitherto reported. Most cases are mild and short-lasting and a longer duration of symptoms seems to be predictive of late sequelae. A clinical diagnosis of cerebellar ataxia after MMR and the exact frequency of this adverse event remains to be tested in prospective studies.

Age Factors↗
PubMed2000

Pressure transfer between intracranial and cochlear fluids in patients with Meniere's disease.

OBJECTIVES: To elucidate the pressure transfer between intracranial and labyrinthine fluids in patients with well-defined unilateral Meniere's disease. STUDY DESIGN: Eleven patients previously exposed to hypobaric pressure agreed to be investigated further with the tympanic membrane displacement (TMD) technique. TMD was used to indirectly analyze perilymph pressure changes as the result of changes in body position. METHODS: Repeated measurements for both the diseased and the healthy ears were made with the patients supine and then in a sitting position. The TMD parameters for the maximum inward displacement, the Vi, and the mean volume displacement, the Vm, were calculated and compared. RESULTS: The paired comparison showed statistically significant larger Vi values for both ears in the supine position. A similar tendency was observed for the Vm value. This difference of the Vi was significantly larger for the diseased ear compared with the currently healthy ear. The results were compared to the audiometric and electrocochleographic results previously obtained on the same patients when they were subjected to hypobaric pressure. Patients who experienced the largest differences in hearing level thresholds in the lower frequencies also showed the greatest differences in TMD values as the result of postural changes. CONCLUSIONS: Despite the limited number, the statistically supported results suggest a relation between the efficiency of the routes of pressure transfer and the observed effect of hypobaric exposure. The results also indicate that for the patients tested, the routes of communication are more effective in the diseased ear than in the healthy ear--a condition that may relate to the pathogeneses of Meniere's disease.

Adult↗
PubMed1998

[TSH-receptor blocking antibodies in juvenile thyrotoxicosis].

The case presented is a 12 year-old girl with hyperthyroidism due to juvenile Grave's disease, who during the course of treatment developed hypothyroidism due to TSH-receptor blocking antibodies, measured by bioassay. The bioassay used was performed on CHO-R cells measuring c-AMP. The role of radioreceptor assays and bioassays in measuring TSH receptor antibodies in hyper- and hypothyroid Graves' disease in discussed.

Age Factors↗
PubMed1998

Long-term test-retest reliability of category loudness scaling in normal-hearing subjects using pure-tone stimuli.

The present study investigates the test-retest reliability of category loudness scaling with pure tones for each of the scaling categories: 'very soft', 'soft', 'OK', 'loud', 'very loud' and 'too loud' at the audiometric frequencies 0.5, 1 kHz, 2 kHz and 4 kHz. Category loudness scaling at two sessions separated by between 1 and 4 weeks was obtained from 16 normal-hearing subjects who all had normal otoscopy, present acoustic reflexes at audiometric frequencies 0.5-4 kHz and middle ear pressure within +/-50 daPa. Intra-subject between-session reliability was found not to be frequency dependent, and comparison with other studies revealed that reliability is not dependent on the applied stimulus signal. Test-retest reliability varied between the different categories: In the categories 'very soft', 'loud', 'very loud' and 'too loud' the test reliability is in the same range as found for hearing thresholds determination, whereas for the 'soft' and 'OK' categories it is poorer. The greater uncertainty for intermediate levels should be considered when using category loudness scaling, e.g. for calculating hearing aid parameters.

Adult↗
PubMed1996

The influence of spontaneous otoacoustic emissions on the amplitude of transient-evoked emissions.

The aim of the study was to analyse whether the presence of spontaneous otoacoustic emissions (SOAEs) in a group of normal-hearing adults is related to larger transient evoked otoacoustic emission (TEOAE) amplitudes when compared to a similar adult population without SOAEs. Twenty-four normal-hearing subjects participated in the investigation. They were selected to form two groups of 12, one containing only subjects with measurable spontaneous emissions, the other of members who had no measurable spontaneous emissions. Each group comprised 7 males and 5 females. TEOAEs were recorded in both linear and non-linear mode, and equivalent sound pressure levels in different octave frequency bands were calculated. For each frequency band, the comparison of the equivalent sound pressure levels in the two selected groups showed statistically significant differences. Therefore, when normative TEOAE data were collected with the purpose of establishing a normative reference for the assessment of cochlear hearing loss, it is mandatory to search for and, when pertinent, to compensate for the presence of SOAEs.

Adolescent↗
PubMed1995

[Agenesis of the corpus callosum].

This article presents ten children with agenesis of the corpus callosum diagnosed during the period 1978-1992. The children were re-examined in 1992, and the results of the examination compared with the results of other authors. Among the ten children, five had other cerebral anomalies, six had eye anomalies, six were mentally retarded and two suffered from epilepsy. There was one boy with inversion on chromosome no. 1, one girl with Aicardie's syndrome, two sisters with agenesis of the corpus callosum (ACC), one of whom was suffering from diabetes insipidus, and two brothers with Walker Warburg's syndrome. ACC is often associated with mental retardation, epilepsy and eye anomalies and may be found associated to many different syndromes.

Abnormalities, Multiple↗
PubMed1995

Calibration of ipsilateral stimulus transducer for acoustic reflex measurements.

Pure-tone Reference Equivalent Threshold Sound Pressure Level (RETSPL) of the ipsilateral stimulus receiver for acoustic reflex measurements on Madsen Electronics type Zodiac 901 impedance audiometer is provided. The results, obtained from 20 normal-hearing subjects, are achieved by comparing hearing threshold levels measured using a TDH 39 telephone (calibrated to ISO 389) with thresholds recorded using the ipsilateral stimulus insert phone. The calibration is referenced to an IEC-711 ear simulator and comprises the following frequencies: 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000, 6000, 8000 Hz.

Adult↗
PubMed1994

[Invasive blood pressure measurements. Factual safety].

Intra-arterial blood pressure measurement is often used in patients with unstable haemodynamics. The demand for accuracy in such measurements is high. Usually these demands are fulfilled, but situations can occur where the dynamic characteristics of the system are exceeded. In order to acknowledge this situation, one must be aware of these dynamic characteristics. The significance of the system's resonance frequency and damping is described. A method to control the usability of the system is described.

Blood Pressure Determination↗
PubMed1994

[Keloid of the external ear].

Keloid formation is an unpredictable complication to normal scar tissue development. The etiology is unknown, although an individual predisposition may be present. There is a regional propensity for the head, neck and upper torso. The treatment is difficult, and this should be taken into consideration when cosmetic procedures are being contemplated. This type of surgery should be avoided in individuals with previous keloid formation. Four cases of keloid formation, two after ear lobe piercing and two after otoplasty are presented and a satisfying outcome of surgical revision with ensuing steroid medication is reported.

Adolescent↗
PubMed1993

Growth of distortion product otoacoustic emissions with primary-tone level in humans.

This study addressed the hypotheses that the growth of the level of distortion product otoacoustic emissions (LDP) with primary-tone level reflects the behavior of a third-order nonlinear polynomial system, and that two sources exist for these distortion products. The results indicated that the 2f1-f2 otoacoustic emission in humans can be measured over a much larger stimulus range than reported previously, even for stimuli (L1 = L2) as low as 10 dB SPL (re 20 microPa). The input/output functions are best described as a straight line with a rate of growth of about 1 dB/dB of stimulus level. For stimulus levels at which metabolically active, nonlinear cochlear processes are in operation, the system does not behave as a simple third-order nonlinear polynomial. Small plateaus and sharp discontinuities or 'notches' can occur in the functions at stimulus levels of approximately 55 dB SPL. These characteristics are consistent with the notion of two separate sources of the LDP, one at low stimulus levels, and one at high levels. An alternative explanation is that the measured otoacoustic emission does not represent only the activity at a single location along the basilar membrane but includes the effects of interactions among similar signals arising from multiple locations, or from the original source via multiple paths.

Acoustic Stimulation↗
PubMed1993

Distortion product otoacoustic emissions. The influence of the middle ear transmission.

Distortion product otoacoustic emissions (DPOEs) were recorded in 8 normal hearing subjects (16 ears, mean age 37) in order to evaluate the sensitivity of the DPOE amplitudes as a function of pneumatic changes (-400 to +200 daPa) in the external ear canal. The responses were collected using time averaging and subsequent FFT-analysis of the collected data. Distortion products were measured at the following geometric mean frequencies: 1,000, 2,000, 4,000, 6,000 and 8,000 Hz. The results show that the amplitudes of the distortion products depend on an optimal transmission through the middle ear, and that measurements of DPOEs should always be preceded by determination of the middle ear pressure. The present findings are in good agreement with investigations based on evoked otoacoustic emissions published by other researchers.

Acoustic Impedance Tests↗
PubMed1993

Clinical significance of probe-tone frequency ratio on distortion product otoacoustic emissions.

Parametric variations in the ratio of primary-tone frequencies were explored to optimize the amplitude of the 2f1-f2 distortion product otoacoustic emission for clinical purposes. Ten ears from 5 normally hearing human subjects were examined with primary tones geometrically centred around the standard audiometric frequencies of 0.5, 1, 1.5, 2, 3, 4, 6 and 8 kHz. The distortion product at the frequency 2f1-f2 (f1 < f2) was measured at six probe tone frequency ratios (f2:f1) varying between 1.15 and 1.40 using equal level primaries of 75 dB SPL. The results showed that a single f2:f1 ratio between 1.20 and 1.25 provides a reasonable value for clinical use in that it optimizes the magnitude of the distortion product at 2f1-f2, provides for sufficient resolution in the test frequency range, and is applicable to the standard clinical test frequencies.

Acoustic Stimulation↗
PubMed1993

Clinical significance of relative probe-tone levels on distortion product otoacoustic emissions.

The effect of systematic variations in the relative levels (L1, L2) of two primary tones (f1, f2) on the amplitude of the distortion product otoacoustic emission (DPOAE) at 2f1-f2 and f1 < f2 was investigated in 14 ears from 7 normally hearing human subjects. The primary tones (f2:f1 = 1.23) were geometrically centred at the standard clinical frequencies of 0.5, 1, 1.5, 2, 3, 4, 6 and 8 kHz. The quantity L1-L2 was varied systematically from -10 dB through + 10 dB with L2 held constant at 75 dB SPL for negative values, L1 held constant at 75 dB SPL for positive values, and L1 = L2 = 75 dB SPL at 0 dB relative difference. The maximum amplitudes of the distortion products were generated when L1 = L2 at all geometric centre frequencies except 8 kHz. The reduction of the DPOAE with reduction of L1 was linear at a rate that gradually increased as a function of geometric mean frequency. To a lesser extent, the reduction of the DPOAE with reduction of L2 also was linear but at a rate that systematically decreased as a function of geometric mean frequency. The results suggest, that to maximize the level of the distortion product for clinical purposes, the relative levels of the primary tones should be equal to each other, at least when overall stimulus levels are around 75 dB SPL and f2:f1 = 1.23.

Acoustic Impedance Tests↗
PubMed1992

Keloids of the external ear.

Keloid formation is a rare complication of normal scar tissue development, also to the surgeon who performs surgery on the external ear. We are presenting 4 cases of keloid formation which occurred after ear piercing in 2 cases and after otoplasty in another 2 cases. The treatment of keloid formation caused difficulties and is not unequivocal. Therefore we wish to present our experiences as we have seen no cases of keloid formation after otoplasty described in the literature.

Adult↗
PubMed1991

Drugs and femoral neck fracture: a case-control study.

Two hundred consecutive patients with femoral neck fractures (FNF) and 200 controls matched by age, sex, nursing home residency and number of admissions within the last 2 years, were interviewed about recent drug use. The matching criteria were chosen to achieve case and control groups that were comparable with regard to overall physical disability. Thus a preliminary study had shown FNF to be strongly associated with nursing home residency and to be correlated with the number of recent hospital admissions. FNF was found to be negatively associated with use of coronary drugs (OR = 0.27; 95% CI = 0.11-0.70) and positively associated with drug use in general (OR = 2.00; 95% CI = 1.04-3.05). The OR for the various classes of psychotropic drugs was consistently greater than 1., although this was not statistically significant. An inherent problem in interpreting such findings is that underlying disease may predispose the subject to both FNF and drug use, thus creating a non-causal relationship.

Aged↗